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Calculation Models of Mass Action Concentrations for Metallic Melts Involving Monotectic

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Journal of university of science and Technology beijing 2001年第4期8卷 248-253页

作者： Jian Zhang Metallurgy school, university of science and Technology beijing, beijing 100083, china Metallurgy school University of Science and Technology Beijing Beijing 100083 China

Based on the phase diagrams, measured activities as well asDeltaG(m) and DeltaG(xs), calculating models of mass action concentrations for metallic melts involving monotectic have been formulated. The calculated results agree with practice on the whole, showing that the models deduced generally can reflect the structural characteristics of these melts. The metastable compounds formed in the melts are of the types A(2)B(3), AB(2), A(2)B(3) or AB and A(2)B(3)+AB etc..

关键词： metallic melts monotectic activity mass action concentration

Equilibrium Precipitation of Niobium Carbonitride in Austenite

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International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 119-122页

作者： Fuming Wang Wenchao Li(Applied science school, university of science and Technology beijing, beijing 100083, china) Applied science school University of Science and Technology Beijing Beijing 100083 China

The equilibrium between niobium carbonitride and austenite has been studied. Experimentally, X-raydiffaction technique was adopted to verify that the precipitates have the same composition and structure. Theoretical-ly, Hillert and Staffansson's regular model about stoichimetric phase was used to describe the thermodynamic proper-ties of multi-component precipitate. Calculated results agree well with experimental values from literatures.

关键词： equilibrium niobium precipitate, austenite

Cross layer scheduling for real-time traffic in multiuser MIMO-OFDMA systems

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The Journal of china Universities of posts and telecommunications 2009年第3期16卷 24-29页

作者： SUN Qiao-yun,TIAN Hui,DONG Kun,ZHANG Ping Key Laboratory of Universal Wireless Communications,Ministry of Education,beijing university of posts and telecommunications,beijing 100876,china Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

A novel cross layer scheduling algorithm is proposed for real-time （RT） traffic in multiuser downlink multiple-input multiple-output orthogonal frequency division multiple access （MIMO-OFDMA） wireless systems. The algorithm dynamically allocates resources in space, time and frequency domain based on channel state information （CSI）, users＇ quality of service （QoS） requirements and queue state information （QSI）. To provide higher data rate and spectrum efficiency, adaptive modulation and coding （AMC） is employed. The proposed algorithm can improve cell throughput and increase the number of users that can be supported while guaranteeing users＇ QoS requirements and fairness among all users. Simulation results indicate that the proposed algorithm can achieve superior performance.

关键词： MIMO-OFDMA cross layer QoS AMC

Influence of magnetic current on the ground state entanglement in an isotropic transverse XY chain

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Progress in Natural science:Materials International 2007年第10期17卷 1147-1151页

作者： Liu Dan1,2 , Zhang Yong3 and Long Guilu1,2(1. Key Laboratory for Atomic and Molecular Nanosciences, and Department of Physics, Tsinghua university, beijing 100084, china 2. Center of Quantum Information science and Technology, Tsinghua National Laboratory for information science and Technology, beijing 100084, china 3. Institute of Physics, school of sciences, beijing university of posts and telecommunications, beijing 100876, china) Key Laboratory for Atomic and Molecular Nanosciences and Department of Physics Tsinghua University Beijing 100084 China

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ>3, namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.

关键词： Heisenberg-XY chain magnetic-current phase transition.

Context-aware end-to-end QoS diagnosis and quantitative guarantee based on Bayesian network

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The Journal of china Universities of posts and telecommunications 2010年第6期17卷 106-112页

作者： LIN Xiang-tao,CHNEG Bo,CHEN Jun-liang,QIAO Xiu-quan State Key Laboratory of Networking and Switching Technology,beijing university of posts and telecommunications,beijing 100876,china State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

To support quality of service （QoS） management on current Internet working with best effort,we bring forth a systematic approach for end-to-end QoS diagnosis and quantitative guarantee. For QoS diagnosis,we take contexts of a service into consideration in a comprehensive way that is realized by exploiting causal relationships between a QoS metric and its contexts with the help of Bayesian network （BN） structure learning. Context discretization algorithm and node ordering algorithm are proposed to facilitate BN structure learning. The QoS metric is diagnosed to be causally related to its causal contexts,and the QoS metric can be quantitatively guaranteed by its causal contexts. For quantitative QoS guarantee,those causal relationships are first modeled quantitatively by BN parameter learning. Then,the QoS metric is guaranteed to certain value with a probability given its causal contexts tuned to suitable values,that is,quantitative QoS guarantee is reached. Simulations with three sequential stages：context discretization,QoS diagnosis and quantitative QoS guarantee,on a peer-to-peer （P2P） network,are discussed and our approach is validated to be effective.

关键词： context context discretization QoS qualitative diagnosis QoS quantitative guarantee Bayesian network

Relaying strategy for peer-to-peer content distribution based on genetic algorithm

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The Journal of china Universities of posts and telecommunications 2010年第2期17卷 85-91页

作者： HE Qian ,MENG Xiang-wu,SHANG Yan-lei,CHEN Jun-liang State Key Laboratory of Networking and Switching Technology,beijing university of posts and telecommunications,beijing 100876,china State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

This article proposes a cooperative relaying strategy to efficiently utilize the relaying resources of Interact service providers （ISPs）, speedup distribution and save server bandwidth costs. ISPs cooperatively relay for each other, and peers assist in distributing and fetching the content as near as possible. Base on the fluid model, a constrained model is derived to get optimized global distribution performance in the channel-based system with limited relaying resources. The multi-objectives of the model are minimizing the average distribution time and the distribution time of the slowest channel. Genetic algorithm （GA） is designed to solve the optimization problem. The relaying strategy based on GA can be run periodically to update the allocation policy of ISPs. The distribution performance of the relaying strategy is analyzed in the experiments and results show that GA can provide proper solutions for various network topologies.

关键词： content distribution peer-to-peer genetic algorithm cooperative relaying resource allocation

Data-aided synchronization algorithm dispensing with searching procedures for UWB communications

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science china(Information sciences) 2012年第4期55卷 778-788页

作者： REN ZhiYuan 1,JIANG Ting1,ZHONG Yi 2 & ZHAO ChengLin 1 1 Key Laboratory of Universal Wireless Communications,Ministry of Education of china Wireless Network Laboratory,beijing university of posts and telecommunications,beijing 100876,china 2 school of Information Engineering,North china university of Technology,beijing 100041,china Key Laboratory of Universal Wireless Communications Ministry of Education of China Wireless Network Laboratory Beijing University of Posts and Telecommunications school of Information Engineering North China University of Technology

Rapid and accurate synchronization constitutes a major challenge in deploying Ultra-Wideband impulse radio (UWB-IR) for indoor wireless *** paper develops a data-aided (DA) synchro-nization algorithm dispensing with searching procedures for UWB-IR *** adopting a stream of alternating orthogonal pulses,frame-level synchronization can be achieved without channel ***-out utilizing any searching procedure,the timing offset estimator is obtained in a closed *** exhaustive search can be avoided,both computational complexity and synchronization time are *** and comparisons are provided to illustrate the advantages of our design over the alternatives.

关键词： Ultra-Wideband impulse radio synchronization dispensing with searching procedures searching space data-aided estimation

A New Genetic Algorithm Based on Niche Technique and Local Search Method

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Journal of university of science and Technology beijing 2001年第1期8卷 63-68页

作者： Jinwu Xu, Jiwen Liu Mechanical Engineering school, university of science and Technology beijing, beijing 100083, china Mechanical Engineering school Univ. of Sci. and Technology Beijing Beijing 100083 China

The genetic algorithm has been widely used in many fields as an easy robust global search and optimization method. In this paper, a new generic algorithm based on niche technique and local search method is presented under the consideration of inadequacies of the simple genetic algorithm. In order to prove the adaptability and validity of the improved genetic algorithm, optimization problems of multimodal functions with equal peaks, unequal peaks and complicated peak distribution are discussed. The simulation results show that compared to other niching methods, this improved genetic algorithm has obvious potential on many respects, such as convergence speed, solution accuracy, ability of global optimization, etc.

关键词： genetic algorithm (GA) niche technique local search method

Dynamic weighted random load balancing algorithm for SIP application server

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The Journal of china Universities of posts and telecommunications 2009年第4期16卷 67-70页

作者： TENG Sheng-bo,LIAO Jian-xin,ZHU Xiao-min State Key Laboratory of Networking and Switching Technology,beijing university of posts and telecommunications,beijing 100876,china State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China

A new load balancing algorithm named dynamic weighed random （DWR） algorithm for the session initiation protocol （SIP） application server cluster is proposed. It uses weighted hashing random algorithm that supports dialog in the SIP protocol to distribute messages. The weight of each server is dynamic adaptive with feedback mechanism. DWR insures that the cluster is balanced, and it performs better than the limited resource vector （LRV） algorithm and minimum sessions first （MSF） algorithm.

关键词： dynamic load balancing weighted random sip application server